In the art of steelmaking, hot metal mixer cars are used to transport loads of molten metal from one location in a steel plant to another location. Such cars are frequently moved by rail using specially designed carriages which permit the large cars to negotiate horizontal curves in the track.
One type of mixer car in common use comprises a transportable, elongate, refractory-lined cylindrical vessel suitably mounted for rotation about its longitudinal axis. Portability of the vessel is achieved by mounting its rotational bearings on spaced apart railroad-type trucks with the vessel spanning the gap therebetween. The vessel is also provided with a pouring spout which permits the discharge of molten metal when the vessel is tilted.
In addition to the components of the mixer cars which permit longitudinal rotation of the car, the trucks include bearing systems which permit the individual trucks to rotate horizontally about a vertical axis. Typically a rigid bolster on the truck supports the car and longitudinal rotational components, a ceterplate member being provided on the bottom of each bolster. These centerplates engage mating sockets on the trucks. In one known design, the centerplate is generally convex and is designed to rest against a generally concave lower socket member. This type of system is described in U.S. Pat. No. 4,135,703 issued Jan. 23, 1979 to Nagati et al. for "Mobile Hot Metal Mixer." In another type of prior art design the centerplate comprises a generally circular centerplate having a planar bearing surface adapted for being received in a circular socket.
One problem with the latter type of mixer cars is the wear which occurs to the centerplate and socket. One solution which has been suggested includes providing a vertical, wear-resistant sleeve about the sides of the socket and a planar wear-resistant disc on the bottom of the socket. While this design has resulted in reduced downtime and permits relatively easy repair of the bearing assembly, it has been found that the sleeves can be displaced vertically under operating conditions that force angular movement of the span bolster with respect to the centerplate. A wear liner design which overcomes the above-noted disadvantage of the prior art would be a significant advance in this technology.